This invention relates to pressure regulators and is especially directed to the small, simple regulator used in conjunction with gas appliances. A typical gas appliance pressure regulator is shown in U.S. Pat. No. 2,979,067.
In this type of regulator, a body, typically a metal casting, provides a gas flow path from an inlet past a valve seat to an outlet. A diaphragm is mounted in the body defining two chambers with a spring and the atmosphere exerting a pressure on one face of a diaphragm and with the gas being controlled exerting a pressure on the opposite face of the diaphragm. A valve stem is carried by the diaphragm and moves a valve member toward and away from the valve seat for controlling gas flow.
In earlier designs, both the valve member and the valve seat were made of metal and both had to be machined to close tolerances to achieve the desired fit. The aforesaid U.S. Pat. discloses a regulator with a soft seat, that is, a grommet of a resilient material such as rubber, mounted in the body for engagement with the moving metallic valve member.
However, this design has certain disadvantages. The grommet has a stressed section for mounting in the body and an unstressed section serving as the seat, and close tolerances are required on both the grommet and the body for proper installation. Also, the valve member carried on the stem has to be pushed through the grommet during installation with the result that the grommet is made sufficiently resilient to receive the entire valve member. With this construction, there is the possibility of the valve member moving into and sticking in the grommet during operation.
It is an object of the present invention to provide a new and improved pressure regulator incorporating a soft seat design while overcoming the disadvantages of the earlier design. A further object is to provide such a regulator with a rigid valve seat in the body and a resilient annular valve insert carried on the stem. A specific object is to provide such a regulator wherein the valve insert may be pushed on to the valve stem, with the valve stem being of a size to prevent passage through the valve seat. Other objects, advantages, features and results will more fully appear in the course of the following description.